I have a string like the following:

desc=Did you know 2 + 2 \= 4?

I want to split each chunk of that string into segments separated by the equal signs. I can't just split on the equal signs because the text has an equal sign in it. I need to split on the non-escaped equal signs.

@parts = split(/(?<!\\)=/,$str);

This is called positive and negative look behind.

In PHP the only difference is that you have to double escape your \

$parts = preg_split('/(?<!\\\\)=/',$str);